1. Field of the Invention
One or more embodiments of the invention are related to the field of virtual reality systems. More particularly, but not by way of limitation, one or more embodiments of the invention enable a virtual reality headset that tracks motion of a user's head relative to a vehicle, and that renders a virtual reality display based on this relative motion.
2. Description of the Related Art
Virtual reality systems are known in the art. Such systems generate a virtual world for a user that responds to the user's movements. Examples include various types of virtual reality headsets and goggles worn by a user, as well as specialized rooms with multiple displays. Virtual reality systems typically include sensors that track a user's head, eyes, or other body parts, and that modify the virtual world according to the user's movements. The virtual world consists of a three-dimensional model, computer-generated or captured from real-world scenes. Images of the three-dimensional model are generated based on the user's position and orientation. Generation of these images may require rendering of the three-dimensional model onto one or more two-dimensional displays.
Many virtual reality systems known in the art use sensors that measure movement of a user's head relative to a fixed reference frame such as the Earth. For example, virtual reality headsets may use inertial sensors, such as accelerometers and gyroscopes, and magnetometers. While these sensors may work well for a user in a stationary environment such as a room, they do not work correctly when the user is in a moving vehicle. As the vehicle changes position and orientation, for example when a car goes around a curve, the headset sensors interpret the vehicle motion as motion of the headset. The virtual reality system then updates the display to reflect this apparent motion. This change in display is confusing for the user, since the user did not deliberately make a motion of his or her head. There are no known virtual reality systems that correctly measure the head motion of a user while the user is in a moving vehicle. A correct measurement of head motion while in a vehicle should track the motion of the head relative to the vehicle, rather than the absolute head motion relative to a fixed frame such as the Earth.
For at least the limitations described above there is a need for a virtual reality headset with a relative motion head tracker.